1. Field of the Invention
The invention relates to a process for producing a tool which is provided with at least one blade and is intended for the machining of a workpiece. More particularly, the invention relates to a process for producing a reaming tool and preferably for producing a drilling/reaming tool. The invention also relates to a tool produced in particular by this process, in particular a drilling/reaming tool.
2. Background Information
A drilling/reaming tool is disclosed, for example, by DE 101 44 241 B4. The drilling/reaming tool described therein has two main (drilling) blades, which are respectively assigned a spiraled main chip flute, which is incorporated in a main body of the tool. Additionally provided circumferentially are three reaming blades, which are spaced apart from one another in the circumferential direction and protrude in the radial direction somewhat beyond the main blades. The reaming blades in this case directly adjoin the main blades. Each reaming blade is assigned a reaming flute, which is likewise formed in a spirally running manner in a heel of the main body between the two main chip flutes.
Such drilling/reaming tools serve for producing a drilled hole and for the simultaneous finishing operation on the wall of the hole with the aid of the reaming blades. It is important here for machining to be as highly accurate as possible, in order to achieve the desired surface quality of the wall of the hole. Also among the decisive factors here is effective transporting away of the chips. Here it must be avoided in particular that a chip becomes caught between the wall of the hole and the tool, which would result in the machined wall of the hole becoming damaged. At the same time, the transporting away of the chips becomes more difficult as the depth of the drilled hole increases.
Cutting tools, such as drills, milling cutters or reaming tools as well as parts thereof, such as for example cutting inserts, are often provided with coatings—depending on the intended application and requirement—for example to increase the wear resistance and/or to improve the sliding properties.
U.S. Pat. No. 5,354,155 discloses a drilling/reaming tool which has a conically tapering drill region and a reaming region adjoining thereto. A main body is in this case provided in the drill region with a diamond coating, which is adjoined in the reaming region by a second diamond coating, different from the first, and finer. The coatings have in this case been applied by means of a plating process.
US 2009/0116913 A1 discloses a reaming tool which has PCD cutting inserts (polycrystalline diamond) and is additionally provided with a diamond-like carbon coating (DLC coating).
US 2007/0298280 A1 discloses a cutting tool with a multilayered construction.
For cutting tools for rough machining, such as drills or milling cutters, often coatings with a great layer thickness in the range of 10 μm or more are applied, in order to achieve a wear resistance which is as great as possible.
This leads in the region of the blades to a rounding on the cutting edges. Sometimes, even lug-like thickenings form there. Such roundings are disadvantageous in the case of fine machining tools, such as for example reaming tools, and have an adverse effect on the surface quality of the machined workpiece. There is also the risk of such a thick coating in the region of the cutting edge being damaged and peeling off during the cutting operation.